class Person {
    constructor (name) {
        this.name = name
    }

    say() {
        console.log(`hi, my name is ${this.name}`)
    }
}

class Student extends Person {
    constructor(name, number) {
        super(name)
        this.number = number
    }

    hello() {
        super.say()
        console.log(`my school number is ${this.number}`)
    }
}

const student = new Student('jack', 200)
student.hello()